Electrostatic separator.



110.840,81. PATENTBD JAN. a, 19o?.

P. H. WYNNB.

ELEGTROSTATIG SBPARATOR.

APPLICATION FILED JAN.20. 1905.

2 SHEETS-SHEET 1.

,Ima/enterar fwrfragy..

No. 840,815. PATENTED JAN. 8, 1907. P. H. WYNNE.

ELEC'I'ROSTATICV SEPARATOR.

APPLICATION FILED JAN.20. 1905.

UNITED STATES PATENT QEEICE.

t PHILIP HENRY WYNNE, oF BosToN, MASSACHUSETTS, ASSIGNoR, BY MESNE ASSIGNMENTS, To HUEE ELEcTRoSTATIo-SEPARATOR coM- PANY, A coRPoRATIoN OF` MAINE. l

ELECTROSTATIQ SEPARATQR.

Specification of Letters Patent.

Patented Jan. 19o7.

Application mea January zo, 1905. serial No. 241,981.

A a citizen of the United States, and a resident of Boston, in the county of Suffolk and IState of Massachusetts, have invented neW and useful Improvements in Electrostatic Separators, of which the following is a specification.

My invention relates to the art of electrostatic separation, concentration, or classifica--` tion of the components of heterogeneous mixtures` of solid material-such as, for i11-l stance, metallic ores and the gangues wherewi-th they are mixed; and it consists in improved apparatus whereby the applica tion of static electricity, to the components ofsuchl mixtures 1s regulated with respect to the time period of said application.

As elaborated in an application for Letters Patent of the United 'States heretofore filed by me on or about August 2, 1904, Serial No. 219,240', foran improved method of electrostatic separatiomit had been observed that the unregulated application of potential to the electrodes of an electrostatic separator resulted in the communication of the charge to more than one componentof a mixture, `.so that the attempted classification 4according to conductivities Was very largely defeated,

as many substances which under other conditions might be separately classed as conductors -and non-conductors behaved .under the said conditions of electrostatic separa-A tion with unregulated otential, alike 'as con- 1 ductors. The process( escribed-in mysaid application is characterized by the regulation* in respect to time of the application 'of the static charge at the electrodes of a separator to the materials to be separated or classified.V

I had discovered that although many substances aie, under conditions of continuously-applied potential, similarly conductors of electiicity, the diiierences in degree between their conductivities is manifested by differences in the elapsed times required for them toi'assume the potential of the body wherewithvl they are brought into effective contact for the purpose of receiving the separative .electriication. Therefore by lreducing the time duration of the potential `applied to the charging-body I was enabled to diierentiate between substances which under conditionsof substantially continuous potential exhibited no sufficient distinction.

The subjectof thepresent specication is an. improvement in yapparatus for' electrostatic separation; and it consists in itspreferred formpf the separator-electrodes, a source of potential, and connections between the source and the electrodes, which comprise means for interrupting the communicatrodes or for regulating the durationol' each such communication of. potential. My invention may, however,v be carried out and embodied in an apparatus which, in connection with the electrodes of a static se arator, comprises a source of otential of W ich the structure andmode 'o operation in itself inivolve the communication of effective potential intermittently to the electrodes. 4

Under the conditions of ine comminution of materials4 to-be treated and the high potentials which have been found most adeconductive particles of alcomminuted mass the'ftime actually required to charge a conductor by'eifective contact with an electrode is so extremely short that potential whereof the fluctuations would ordinarily be con- `s idered very rapid nevertheless acts .as if it lwere practically continuous in relation to the. said time periods of charge for comminuted matter. It must be borne in mind, therefore, that the definitive terms used herein are referable 4to those conditions which are peculiar to electrostatic separation'and that it'may well be, for instance, that the potential derived from an alternating-current generator may, unless the transmission of potential to the separate electrodes is specifically regulated, produce at each alternation in phase a potential which, in effect, is continuous, although apparently and according to ordinary standards it is very rapidly alternating.

In the drawings hereto annexed, Figure 1 illustrates diagrammatically and partly in perspective a form in which my invention may be embodied. Fig. 2 illustrates diagrammatically the interrupter or f commutator which forms a component art of the apparatus shown in-Fig. 1. `ig. 3 shows diagrammaticall and partly in perspective another form o apparatus embodying my invention, and Fig. 4 shows in skeleton form and diagrammatically a specific form of intion of potential from the source to .the elecquate eifectively to .separate by repulsion IOO IOS

posed of hard rubber or other good insulating material, the-said cylinder mounted upon a shaft, as at R. v PP represent the terminals of a generator of potential-say, in this case, an electrostatic influence or friction machine. E E represent the two electrodes of an electrostatic separator whereof the-electrode E (shown in cross-section) is a rotating cylinder havingian electroconductive surface and the electrode E is a -wire surrounded ,preferably bg an 'insulating-envelop. A `'hopper iH a ove the electrodes contains and delivers the mixed material which falls upon the surfaoe of the rotating electrode E, and between 'the electrodes E E there is mounted a ydi'- vider D, of insulating material. The terminals P P are connected with theelectrodes E E by meansof the wires 1 2 17 18,the brushes 3 4 19 20, `and the interrupt'erwhich iscon'- 'tained and #carried by the rcylinder R,pres `ent'ly'to'berlescribed-` Reference to .Fig 2 'will enable the construction of the interruptor to be more clearly tunderstood. yIn Fig. 2 the surface vof the 'cylinder R is shown as developed. U on the surface of 'the insulating material -o' which .the cylinder is composed there are secured Acontact-strips a b a -bJ-and c d c d and likewise the .discharging-plates M N. Strip a is connected to strip a', strip '1) to b', -strip c to strip d", and strip d to strip c. The brushes '3 4 19'20 are mounted so as to `makecontact with the strips a b t a" and cd d c as the -cyl- Rinder R (Fi-g. 1) rotates in the direction of the scurved arrow. As willA be seen from examination of Fig. 2, when `the strips a b a fb are in'contact with the hrushesthen electrode E :isi-n connection with negative pole P and the electrode E with the positive pole P.' When Athe relation of the cylinder R ycarries these stri` s `out from under the brushes, the electro second set of stri-ps came in contact with the 'brushes were it not for the discharging-plate M, into contact with which lthe'two brushes '19 20 inmediately come inthe rotationofthe `cylinder R, and the electrodes E E are 'consefqhuentlydischarged. Then in the rotation 'of te `cylinder there -follows an interval of no excitation for theelectrodes E E until the strips c d d c make contact with the brushes 3 4 19 20. lThe connections are now such #that electrode E iis connected with pole P and electrode E with pole P. Again, as the ro- *tation of the cylinder continues the brushes 19 20, comin in contact w-ith the discharg-- i i -plate Np ischarge the electrodes E EH y the above arrangement the duration of successive potential impulses at the electrodes E may be regulated. The strips at a fb c d c d" may be made long or short at wil1',`or, if desired. the pairs of brushes 3 4 19 E E would remain charged until theI 20 can be so mounted that one pair has a desired lead over the other, so that the interval within which all four brushes are in contact with the strips may be quite finely adjusted. Figs. 3 andA 4 illustrate another specific form and embodiment of my invention. As before, P P 'represent the terminals of an electrostatic machine, and EE the electrodes of the electrostatic separator. The wires 1 2 lead from the terminals of the source of potential'to brushes 3 4 and the wires 17 18 tobrushes 19 20, these brushes bearing the same relation electrically to the apparatus as -do the terminals similarly numbered in Fig. 1. Upon the shaft S there are mounted. woodendisks X Y, to which are securedsegmental contact-pieces a b c d a b c d', respectively. These segmental contact-.pieces are symmetrically :arran ed and fare concentric with the axis of :the s Aaft S. i They are also so angularly disposed with relation to the shaft that .the segments afb a b lie between the sameradial planes ,vas also do the seg-ments c d c d. Referring no'w'to Fig. 4, the connection between these segments may be made plainer. The louter segment a is wired directly to the outer segment a and the inner segment b to the inner segment b. lOn the other side the outer segment cis wired to the inner segment d. and the inner segment d to the outer segment gc. The brushes 3 4 19 20 are mounted'so -as to make -contact with the segmental contact-pieces onthe two disks X Y. Upon the rotation of the shaft S in the 'direction indicatedby the arrow the connections between thesource 'of potential P P- and the separator-electrodes E E are .established and broken recurrently. When, as in spectively, with segmental contact-pieces al b b a, electrode E will be ne atively and electrod-e E" 'positively charged. When in the course of rotation of the ysli-ait 'S brushes .3 4

.ments c d d c', respectively, by means of the cross-connections shown in Fig. 4, the relectrode E will be excited positively and the electrode E negatively. With the `Wooden disks X Y s ecial discharging arrangements, like the pla es M N of Figs. 1 and 2, are not ,always necessari, for the reason that .thewood of which the dis sare composed is often sufficientlconductive to discharge the electrodes E E t ough the brushes 19 and 20, provided the supply from .the terminals P P be not left the contact-stri-ps on the disk X. When all four brushesare in contact with the strips, While there is some leakage through the wood of the :disks this is overcome -by the supply from the generative source whereof the poles are P P.' The time limit of excitation of the electrodes E E of the separator depends with this apparatus u on the speed of rotation of the shaft S and tle angular extent of the seg- ICC Fig. 3, the brushes v3:4 `19 20 are in contact, re-

-19 2 0 are brought into contact with .the seg- IIO lkept up as is the case when brushes .3 4'l1ave i mental lcontact-pieces la., b c d a b c d', and by means of these two factors the potential du ration at the se arator-electrodes may be regulated. If it e desired to excite the electrodes E E intermittentl without change of polarity, one pair of the interruptcr connections may b e eliminated b'y omitting or covsuch as shown in Fig What I claim, an ters Patent, is-

ermg one set of segmental contact-pieces,

means to deprive the electrodes of potential in the intervals vbetween the acts of supply.

2. In an electrostatic separator, vthe com- -bination with thcelectrodes, of asource of -bination with the electrodes, of asource of` potential, connections between the source and the electrodes, and means interposed be-y tween the electrodes and the said sourcesubstantially. to deprive the electrodesoi` potential except during predetermineddntervals of time. p

3. In an electrostatic separator, the compotential, 'connectionsl between the source and 'the electrodes, vand means to interrupt recurrently the persistence of effective potenl tial o n the electrodes.

4. In an electrostatic separator, the combination with the electrodes, of a source of potential, Iconnections between the source rupter, recurrently to deprive the electrodes of potential.

5. `In an electrostatic separator, the combination with the electrodes, of a source of 'potentiaL'l -connections between the source and' the electrodes, comprising segmental contact-pieces, `brushes therefor, and means relatively to move the lrushes and segmen-Y tal contact-pieces in order recurrently and alternately to supply the electrodes with potential from the source andv to deprive the electrodes of potential.

vSigned Iy me at- Boston, Massachusetts, this ,10th day of Januar- 1905.

PHILIP VENRY WYNNE. Witnesses:

JSEPH T. BRENNAN, MARGARET A. DANIHER.

'and the electrodes, comprising a rotary inter- 

